The present invention relates to a Time of Flight mass analyser and a method of analysing ions. It is well known to those skilled in the art of Time of Flight mass spectrometer design that one of the factors that limit the resolution of Time of Flight mass spectrometers is the optical alignment between the various components that comprise the mass spectrometer. This is especially important in orthogonal acceleration Time of Flight (“oa-TOF”) mass spectrometers which commonly comprise a set of parallel electric field regions which are delineated by a series of meshes or grids with precise mechanical separation. The location of these optical components are known as the principle planes of the Time of Flight mass spectrometer. Particular attention is paid to the parallelism and flatness of the principle planes which are commonly aligned to within a few microns to enable high mass resolution.
Misalignment of any of the principle planes of an orthogonal acceleration Time of Flight mass analyser such as the pusher electrode, first and second grid electrodes and the ion detector can result in a significantly reduced resolution.
It is desired to provide an improved Time of Flight mass analyser and method of mass analysing ions.